1. Field of the Invention
The invention relates generally to nail polish. More specifically, the invention relates to instantly dry film coatings of nail polish that one can apply to one's nails instead of getting a manicure or brushing on liquid nail polish.
2. Description of the Related Art
People have used nail polish to color or adorn their nails for hundreds of years. Conventionally, nail polish is applied in liquid form by a brush and then must dry. The drying process takes time, during which the nail polish wearer must be very careful of her nails so as not to smudge or ruin her polish job.
Commercially available nail polishes use predominantly ¼-second and ½-second nitrocellulose (approx. 300-800 centipoise as measured by a Brookfield viscometer operating at 60 rpm). The designation of “second” indicates how long a metal ball will take to fall to the bottom of a given-sized drum of the material; the longer the period of time, the greater the viscosity of the nitrocellulose. Adjustments to the viscosity are then made with small amounts (i.e., 1-5 w/w %) higher viscosity nitrocelluloses i.e., 40-60 second and 60-80 second. Such high viscosity nitrocelluloses have never been used at higher concentration than 1-5% because the resulting nail polish would be too thick to apply by brush. The composition of a typical nail polish (also called nail enamel) is approximately 25-32% solids and 68-73% solvents. Of the solids, on a weight/weight percentage, 6-12% is nitrocellulose (¼-second or ½-second), about 6-12% is resin and 6-10% is plasticizer. The remaining contents are typically as follows:
mica and color pigments 8-15%
ethyl acetate 20-30%
n-butyl acetate 20-30%
isopropyl alcohol 5-10%
miscellaneous 3-7%.
Because of the high solvent content, commercially available liquid nail polishes are flammable and must be shipped via ground or water unless indicated for special delivery and handling.
More recently, there have been developments in the field where dry or nearly dry film coatings of nail polish are available for application to a person's nails. Two patents that describe this type of appliqué are U.S. Pat. No. 4,903,840 to So and U.S. Pat. No. 5,415,903 to Hoffman et al.
The So patent, assigned to the instant assignee, teaches a basic method of making self-adhesive nail coatings of this nature. In the So patent, the nail coatings are made by using a mold having a pour hole and a slot or passage for a sheet of adhesively-backed paper to pass through or by. Conventional liquid nail enamel is poured onto the sheet of adhesively-backed paper as it is slowly drawn through the mold. A uniformly coated, adhesively backed nail coating sheet is thus created. The sheet is then dried for a predetermined time and at a predetermined temperature or until the sheet has the nail enamel coating in a semi-solid, yet not completely dried state. The strip is then preferably cut into sets of five fingernail coatings. The sheet is also preferably provided with a ribbon or tear strip which serves to facilitate the individual application of the nail coatings to the fingernails by easing removal of the coatings from the adhesive-backed paper. The sets of coatings, after partial drying, are encased in a substantially air-tight envelope until used.
The Hoffman patent teaches a similar dry nail coating that consists of a film-forming polymer layer containing at least one plasticizer (again, conventional nail enamel), a pressure-sensitive adhesive layer located thereon, and a carrier film or supporting foil which covers the pressure-sensitive adhesive layer and which can be removed and is preferably silicone-treated. The film-forming polymer layer is also covered on the other side (i.e., the top) with a completely removable protective layer which is resistant to the other constituents of the laminate and the materials used in the preparation of the laminate. The Hoffman patent adds little to the teachings of the So patent, other than the addition of the completely removable protective layer provided over the top of the enamel layer, which appears to be conventional in the art at any rate.
It would be desirable to be able to speed up the manufacture process of nail coating laminates. It would also be desirable to provide methods of creating nail coating laminates or appliqués of multiple colors, with patterns, with a metallic finish (heretofore unachievable in nail coating laminates), and the like.
It would also be desirable to achieve a “French manicure” effect, i.e., a white tipped appliqué with a pink, clear, or pearlescent main portion, that is easy to manufacture and then apply. It is additionally desirable to increase the ease with which a user of nail products can use and handle the product when she uses it herself.